Help Slingshot rope

[baskot]

Hello, I want to make slingshot like mechanic but whenever I pull the sphere back it went through the rope. I have tried to make rope length bigger but still not working.

Here's the inspector panel
         

Here's the video, any help would be great thanks.

https://media.giphy.com/media/dAoa4kKJjG.../giphy.gif